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Topic: Minimum start-up time (Read 664 times) previous topic - next topic

ProfePaco

Hi:

I am planning to design a infrared controller. Each time that a button is pushed the Arduino will be powered on and an input will be send to it.

Therefore, I need to know how much time the microprocessor needs to be ready to process inputs (to execute a program).

I will use an Arduino nano or an Attiny85.

Thanks in advance.

Coding Badly

#1
Dec 31, 2011, 08:17 pm Last Edit: Dec 31, 2011, 08:18 pm by Coding Badly Reason: 1

The biggest delay is from a bootloader.  

Assuming the processor does not have a bootloader ... The processor will be ready for business before your brain has time to send a signal to your hand to release the button.

The latest optiboot is very efficient at getting the application started.   I suspect, even with it installed, the processor will be ready for business long before you are.

But, it is fairly easy to test.  Essentially, you would be building a JEOPARDY! button.  You versus the processor.   :D

smeezekitty

IMO, Starting the MCU every time is a poor idea.
The amount of time required for startup depends on the startup fuses programmed.
The lowest setting is no delay so all there is - is 1-2ms of overhead. This setting is not recommended because it gives it very little time to stabilize.
The next setting is 4 ms + 1-2ms overhead. It takes about 5-6 ms to startup.
The longest setting is 64ms + 1-2ms overhead. Total startup 65-66ms. This is usually the default.

Fuse calculator is here: http://www.engbedded.com/fusecalc/
Avoid throwing electronics out as you or someone else might need them for parts or use.
Solid state rectifiers are the only REAL rectifiers.
Resistors for LEDS!

ProfePaco

OK, thanks both, so no problem with delay.


IMO, Starting the MCU every time is a poor idea.


I thought this is the way what a remote control works...  

smeezekitty

Normally you would run it in IDLE mode which reduces the power consumption to a very tiny amount but it is waken by an interrupt (which can be a pin change).
Avoid throwing electronics out as you or someone else might need them for parts or use.
Solid state rectifiers are the only REAL rectifiers.
Resistors for LEDS!

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